/*
 * Copyright 2020-2030 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.wwl.usecase;

/**
 * @author Neil Wang
 * @version 1.0.0
 * @date 2021/6/11 10:56 上午
 */
public class Sum {

    public static int sum(int[] arr) {
        return sum(arr, 0);
    }

    private static int sum(int[] arr, int index) {
        if (index == arr.length) return 0;
        return sum(arr, index + 1) + arr[index];
    }
}
